Pam 00:00
Hey, fellow mathers! Welcome to the podcast where Math is Figure-Out-Able. I'm Pam.
Kim 00:06
And I'm Kim.
Pam 00:06
And this episode is a MathStratChat episode where we chat about our math strategies. Every Wednesday evening, I throw out a math problem on social media, and people from around the world chat about the strategies they use, and comment on each other's thinking.
Kim 00:19
Alright, this Wednesday, the problem was 3,002 minus 1,905. How would you solve this problem? Go ahead and solve it any way you want, and then listen in.
Pam 00:32
So, 3,002 minus 1-9-0-5. 1,905. Alright, go. Can I go first?
Kim 00:39
Sure.
Pam 00:40
So, I'm going to Constant Difference again.
Kim 00:43
Okay.
Pam 00:43
Meaning, I'm going to plunk both those numbers down on a number line and think about how far apart they are but not where they are.
Kim 00:50
Okay.
Pam 00:51
I would like to subtract a number that's delightful. And to me, 1,905 is okay, but it's not as delightful as I wish, so I'm going to take that distance down to... I'm going to shift them both down 5. So, the 1,905 becomes 1,900. And the 3,002 down 5 becomes 2,000...I have to think here...97. Ha, I'm alive. I'm awake. Is that right? Yes. That's 5 down. Okay, so now I end up with an equivalent problem. That's funny. Equipment problem a 2,097 subtract 1, 900. No, I don't like that. Look at that. Look at me. Waking up and not liking what I just did.
Kim 01:31
You want to change? You can change your mind.
Pam 01:33
Do I get to change my mind?
Kim 01:34
Absolutely.
Pam 01:35
Well, now what am I... I got to think about what I'm... Alright, alright, I'm changing my mind. From 1,905. This is thinking live, ya'll, on the podcast right now. I'm going to take 1,905 up to 2000.
Kim 01:48
Okay.
Pam 01:48
So, that's 95. That means I have to add 3,002 also plus 95. So, that's 3,097. So, now I have an equivalent problem of 3,097 subtract 2,000. Yeah, like that better. So, 3097 subtract 2,000 is 1,097.
Kim 02:09
Yeah, I like it. I also like that sometimes you think something is friendly when you shift, and it doesn't end up friendlier, so you just shift again.
Pam 02:20
Just try it again.
Kim 02:21
Yeah, totally fine.
Pam 02:22
Yeah. Yeah, you kind of freed me up that one day when I thought mathematicians could instantly know the best thing to do right off the bat. And we probably do that almost too quickly here sometimes...
Kim 02:32
Yeah.
Pam 02:32
...in MathStratChat. But that was real. That was me thinking, "Hey, yeah, I'm just going to turn 1905 into 1900 Sure, that will..." No, that's not good at all."
Kim 02:40
Yeah, yeah.
Pam 02:41
Or at least, (unclear).
Kim 02:41
Well, because the whole point of Constant Difference is to find an equivalent problem that's nicer.
Pam 02:46
I mean, now that I think about it, 2097 minus 1900. I could still think about the distance between those numbers. Let's just a 1,097 Duh. Like, it's not bad.
Kim 02:58
It is also very real, people, that we have a microphone in our face. So, (unclear)
Pam 03:07
So, my brain caught on that one. When I thought about 2,097 minus 1900, I was thinking removal, not distance. But if that distance is just 100 up to the 2,000, right? And then... Or, I mean a 1,000 up, and then 97. Bam! Alright.
Kim 03:22
Nice. Nice.
Pam 03:23
So close and yet so far. What are you going to do?
Kim 03:26
I also want to shift the distance because that's a little funky, but I actually shifted down a little bit. Because the 3,002 just feels so close to 3,000.
Pam 03:37
Okay. (unclear).
Kim 03:38
So, I shifted to the left to make the new problem 3,000 minus 1,903. On a number line. I said to the left because I shifted on number line. So, my new problem is 3,000 minus 1,903.
Pam 03:55
Okay.
Kim 03:58
And I also found the distance. And, you know, that just feels I Have, You Needy for me, so...
Pam 04:05
Did you just say I Have, You Needy?
Kim 04:08
Is that my new phrase?
Pam 04:09
I think so. That's hilarious. I Have, You Needy. I like. Like, did you just literally go from 1,903 up to 2,000? And that's 97?
Kim 04:19
Yeah, I think because I went 197 in my head. Like, I started looking at the 1903.
Pam 04:27
Yeah.
Kim 04:28
And I went 197. I mean, 1,097 Yeah.
Pam 04:32
Oh, you can see that 1,000.
Kim 04:34
Yeah.
Pam 04:35
I had to see the 97 first, and then the 1000.
Kim 04:37
Oh, yeah, either way. Okay. Cool. 1,097.
Pam 04:41
Yeah, so you often will change the first number in a subtraction problem to be a nice number, and then subtract. And that is not my fave. I would prefer to change the second number in the subtraction to be a nice number.
Kim 04:54
Yeah.
Pam 04:55
Yeah.
Kim 04:56
I think a lot of people will. But you could play I Have, You Need some more. Alright.
Pam 05:02
Sounds good.
Kim 05:03
We can't wait to see.
Pam 05:05
So, then I can be I Have, You Needy too?
Kim 05:09
We need a shirt. I Have, You Needy. Alright people. What are you going to do this week? Join us on MathStratChat. Let us know how you think about the problem, and comment on each other's thinking.
Pam 05:20
Ya'll, we post the problems on Wednesdays around 7pm Central time. When you answer, tag me and use the hashtag MathStratChat. Then join us here to hear how we're thinking about the problem. Ya'll, thanks for being part of the Math is Figure-Out-Able movement because Math is Figure-Out-Able!
